Today is the day that Wall Street has been waiting for.

Here's what you need to know before the opening bell rings in New York:

1. Ready, set, Fed: The Fed is due to announce its interest rate decision at 2 p.m. ET. Fed chair Janet Yellen will host a news conference at 2:30 p.m. ET to explain the thinking behind the central bank's decision. Investors will be monitoring her remarks closely for hints about plans for any further rate rises.

Interest rates are currently near 0%, and they've been at this level since December 2008.

A rate increase would signal that policymakers believe the economy is on solid enough footing to handle higher borrowing costs.

"We've waited so long for this policy move that the initial [market] reaction may be meaningless," said Kit Juckes, a global strategist at Societe Generale. "Beyond the very short term however, the U.S. economy will go on growing, the Fed will hike further, and the dollar will rally through 2016."

(If you want to learn more about the importance of the Fed decision, CNNMoney has compiled a list of "Suggested Reading" for you at the bottom of this article...)